Heat analysis of the plate type and wave type heat sink were carried out by using computational simulation. The heat resistance and air flow of two heat sink models were analysed according to natural and forced convection condition and positions of fan. When a fan was at the position of z-axis and y-axis in forced convection, the heat resistances of plate type heat sink were $0.17^{circ}C/W$, and $0.28^{circ}C/W$ respectively. In the case of wave type heat sink, they were $0.18^{circ}C/W$ and $0.53^{circ}C/W$. As the air flow velocities were averagely $0.386;m/s~3.269;m/s$, air flow velocity of plate type heat sink was faster than that of wave type. In this experiment, it was observed that the plate type heat sink showed a good ability of heat radiation comparing with wave type one.